A 2-D Beam-Scanning Bessel Launcher for Terahertz Applications

This article proposes a novel nondiffractive Bessel beam launcher based on discrete dielectric lens (DDL) antenna with 2-D beam-scanning capability operating at 300 GHz. The terahertz (THz) Bessel beam launcher consists of two identical in-plane rotatable DDLs fed by a commercially available pyramid horn. First, the two thin and lightweight DDLs can transform the quasi-Gaussian beam with spherical phase front from the feed horn into a well-collimated and confined pseudo-Bessel beam. Second, we demonstrate that simultaneous in-plane rotation of the two DLLs in the same and opposite directions can steer the generated Bessel beam in the azimuth and elevation, respectively. Hexagonal dielectric post is employed as the element of the DDL, whose height is tuned from pixel to pixel to realize the required aperture phase distribution. 3-D printing technology was utilized to fabricate the two DDLs aiming at simplifying the manufacturing process and reducing the cost. The theoretically calculated, simulated, and measured results reveal that the designed THz DDL can generate 2-D scanning nondiffractive Bessel beam with a large field of view (FoV) of 86.2° and full azimuth coverage. The proposed 2-D scanning THz Bessel beam launcher can find widespread applications in THz fast noncontact detection, tracking, and imaging systems.